Press forming machine

ABSTRACT

A MACHINE AND METHOD OF PRESS FORMING AN INITIALLY FLOCCULENT CEMENTITIOUS MIXTURE TO PRODUCE A RECTANGULAR, ROUND OR OTHER SHAPED OPEN BOXLIKE PRODUCE SUCH AS A METER HOUSING, THE MACHINE INCLUDING A CORE MOUNTED BETWEEN GUIDE WALLS IN ANGULAR RELATION THEREWITH, A PAIR OF OPPOSED HORIZONTALLY MOVABLE PRESSURE DIES HAVING ANGULARLY RELATED SURFACES PARALLEL TO CORRESPONDING SIDES OF THE CORE AND SLIDABLE BETWEEN THE GUIDE WALLS TO COMPRESS THE MIXTURE AGAINST THE CORE, AND A VERTICALLY MOVABLE PRESSER DIE RING SLIDABLE BETWEEN THE CORE AND THE OPPOSED PRESSER DIES TO EFFECT A SUPPLEMENTARY VERTICAL PRESSING OF THE MIXTURE AND TO SHAPE THE TOP PORTION OF THE PRODUCT, THE METHOD INVOLVING THE INITIAL PRESSING OF A PORTION OF THE PRODUCT TO A PREDETERMINED DENSITY, AND THE REMAINDER TO A PREDETERMINED LESSER DENSITY, THEN PRESSING THE REMAINDER IN A VERTICAL DIRECTION TO ESSENTIALLY THE SAME DENSITY.

June 20, 1972 J. 1.. ROBBINS 3,671,156

PRESS FORMING MACHINE Filed Se t. 4, 1970 4 Sheets-Sheet 1 2 2 ,LI i

INVENTOR.

c/AMEs L BOBB/MS A 770 Eva 5 June 20, 1972 J. L. ROBBINS PRESS FORMINGMACHINE 4 Sheets-Sheet 2 Filed Sept. 4, 1970 I j/ INVENTOR. JAMESLEOBB/NS ATTOEA/E S Jun 20, 1972 J, ROBBINS 3,671,156"

' PRESS FORMING MACHINE Filed Sept. 4, 1970 4 Sheets-Sheet 3 0 i QINVENTOR. 1 U -13; g c/AMES LEoaa/A/s L L w BY m aw June 20, 1972 J. L.ROBBINS 3,671,156

PRESS FORMING MACHINE Filed Sept. 4, 1970 4 Sheets-Sheet 4.

FIG. /4

. INVENTOR. c/AMES L. Boas N5 United States Patent 3,671,156 PRESSFORMING MACHINE James L. Robbins, West Covina, Calif., assignor toBrooks Products, Inc., El Monte, Calif. Filed Sept. 4, 1970, Ser. No.69,797 Int. Cl. B29c 1/00 US. Cl. 425-130 Claims ABSTRACT OF THEDISCLOSURE A machine and method of press forming an initially flocculentcementitious mixture to produce a rectangular, round or other shapedopen boxlike product such as a meter housing, the machine including acore mounted between guide walls in angular relation therewith, a pairof opposed horizontally movable presser dies having angularly relatedsurfaces parallel to corresponding sides of the core and slidablebetween the guide walls to compress the mixture against the core, and avertically movable presser die ring slidable between the core and theopposed presser dies to effect a supplementary vertical pressing of themixture and to shape the top portion of the product; the methodinvolving the initial pressing of a portion of the product to apredetermined density, and the remainder to a predetermined lesserdensity, then pressing the remainder in a vertical direction toessentially the same density.

BACKGROUND OF THE INVENTION It has been the custom for many years tocast open end, rectangular, round or other shaped meter boxes orhousings out of concrete. Such products have low structural strength andare heavy so that damage to the boxes can be substantial, especiallyduring handling, transportation and installation.

SUMMARY OF THE INVENTION The present invention is directed to a machineand method of press forming which is particularly adapted, but notlimited to, the production of meter boxes or housings of rectangularshape, open top and bottom, and intended to be set flush in the ground.The invention is summarized in the following objects:

First, to provide a machine and method which is particularly suited forthe compressing of a type of mixture disclosed in Pat. No. 3,204,019,while shaping the mixture into the desired configuration; however, themachine and method is adapted for the forming of cementitious mixturesgenerally.

Second, to provide a machine and method, as indicated in the otherobjects, whereby the compressible mixture is first compressedtransversely about a central core, then compressed axially to form adense mass capable of being removed intact from the press and cured,thereby to produce a product which is not only lighter than concrete,but also much stronger so as to withstand more readily the loads imposedincidental to transportation, installation and ultimate use.

Third, to provide a machine and method, as indicated in the otherobjects, wherein the product may be constructed with thicker walls in,for example, its upper or rim portion yet the mixture is compressedsubstantially uniformly throughout its mass.

Fourth, to provide a machine and method, as indicated in the otherobjects, wherein a rectangular core is secured between guide walls withtwo corners in confronting relation therewith, a pair of horizontallymovable pressing dies having V-shaped operating faces are simultaneouslymovable toward the core to compress an initially loose mass ofcementitious mixture, whereupon a vertical die Patented June 20, 1972DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view of the machine forpress forming a cementitious mixture.

FIG. 2 is a sectional view thereof, taken through 2P4 of FIG. 1, showingthe pressing dies in a retracted position.

FIG. 3 is an enlarged view, taken within Circle 3 of FIG. 2, showing thepressing dies in their extended position upon completion of the pressingoperation, and indicating fragmentarily in plan a completed product,portions of one die and the supporting pallet being broken away toindicate underlying structure.

FIG. 4 is a further enlarged fragmentary plan view, taken within Circle'4 of FIG. 3, showing one corner of the core and adjacent portions ofthe pressing dies, the dies being in their extended position.

FIG. 5 is a similar fragmentary plan view, showing the dies partiallyretracted and in the position assumed when introducing a cementitiousmixture.

FIG. 6 is a fragmentary sectional view at a reduced scale, taken through66 of FIG. 5, showing confronting portions of the core and presser diein position for receiving a cementitious mixture therebetween.

FIG. 7 is a similar view, taken through 7-7 of FIG. 4, showing thepresser die as it appears on completion of the pressing operation.

FIG. 8 is a similar fragmentary sectional view, showing the presser ringinserted between the core and presser die to complete the formingoperation.

FIG. 9 is a fragmentary sectional view, at a reduced scale, takenthrough 99 of FIG. 5, showing the confronting portions of the core andpresser die in position for receiving a cementitious mixture.

FIG. 10 is a similar fragmentary sectional view, taken through 10-10 ofFIG. 4, showing the core and presser die on completion of the pressingoperation.

FIG. 11 is a similar sectional view, showing the vertical presser ringafter completion of its operation.

FIG. 12 is a fragmentary sectional view of the core and a presser die,shown in their separated position with uncompacted cementitious materialtherebetween and showing a web forming die, incorporated in the presserdie.

FIG. 13 is an enlarged fragmentary sectional view, taken within Circle13 of FIG. 12, showing the web forming die in its web forming position.

FIG. 14 is a fragmentary sectional view, showing a modified embodimentof the web forming die.

SPECIFICATION The machine and method for press forming is particularlyadapted to the forming of a cementitious mixture, which is initially ina loose flocculent state and capable of compression to a third or a halfof its initial volume. An example of a mixture suitable to the purposesof the present invention is the mixture described in Pat. No. 3,204,019,issued Aug. 31, 1965. s

The machine and method is primarily intended to form meter boxes orhousings which are rectangular in plan and open at their top and bottomends. However, the machine and method may be adapted to form roundstructures or structures of other shapes. More particularly, the meterbox 1 illustrated has a lower portion 2 having relatively thin uniformwalls, except for the taper needed to remove the meter box from themachine, and a relatively thick upper portion 3 which is provided withan internal shoulder 4 to support a cover. Also, externally,

the end walls may be straight with an internal offset 5; whereas, theside walls may be offset externally, as indicated by 6, and internallyas indicated by 7. Finally, the corners of the upper portion are roundedinternally as well as externally; whereas, externally the lower portionsof the meter box may be beveled at the corners, as indicated by 8.

The external offset 16, which may include the ends as well as the sides,accomplishes two purposes. (1) The meter box is stronger so as to betterresist rough treatment during handling, shipping and installation. (2)The shoulders formed by the offset provide a means of keeping the meterbox at grade level.

The machine includes a vertical frame structure 9 which supports ahorizontal frame structure 10. The horizontal frame structure 10includes a bottom plate 11, side walls 12, end walls 13 and a top plate14, forming a boxlike structure. At their midportions, the side walls 12are lined with relatively thick plates which form guide walls 15.

The bottom plate 11 is provided with a central opening 16 extendingbetween the guide walls 15. The opening 16 is essentially rectangularwith its sides disposed at a forty-five degree angle to the longitudinalaxis of the frame structure 10. Underlying the opening 16 is a coresupporting grid 17, comprising longitudinal bars. Supported on the grid17 is a core mounting plate 18 on which is secured a rectangular core19. The core tapers upwardly and is provided with rounded corners 20.Also, the core tapers upwardly to permit withdrawal of the finishedproduct and extends higher than the finished product. The core ispositioned with its side walls defining forty-five degree angles withthe guide walls 15. The top wall has a clearance opening 21.

The horizontal frame structure 10 receives a pair of opposed horizontalpressing dies 23, which include die surfaces '24 and 25 confronting thecore 19, and disposed at a forty-five degree angle to the guide walls15. The upper portions of the die surfaces are joined by a curvedsurface 26, whereas, their lower portions are joined by beveled surfaces27. The lateral extremities of the die surfaces taper to relativelysharp edges and terminate in beveling extensions 28. In the regioncorresponding to the cured die surfaces 26, the guide walls are providedwith curved recesses 29, complementary to the upper portions of the diesurfaces 24 and 25.

Each pressing die 23 is moved horizontally by a hydraulic unit 30, thebase of which is attached to a corresponding end wall 13'.

The vertical frame structure 9 extends above the horizontal framestructure 10' and guides a vertical pressing die 31, having a downwardlyextending internal rim 32. The pressing die 31 is operated by ahydraulic unit 33, carried by the vertical frame structure.

A pallet frame 34 is removably mounted on the grid 17 and surrounds thecore mounting plate 18, which has the same dimensions as the base of thecore 19. The pallet frame includes beveled portions 35 so that thepressing die may move partially over the pallet frame in the course offorming the product. When the pallet frame is removed, the grid 17permits excess mixture to be cleaned from the core and die surfaces andremoved.

Mounted at the bottom of the frame structure 10 is a hydraulic unit 36which supports a mounting plate 37, from which extend upwardly directedejector rods 38, positioned to engage the pallet frame 34 so that whenthe product is completed, it may be raised for removal as indicated inFIG. 1.

The method of press forming a cementitious mixture to produce, asindicated, an open end boxlike product is as follows:

The vertical pressing die 31 is disposed in its upper position initiallyand the horizontal pressing dies are retracted from the core apredetermined distance. The spacing between the core and the bottomplate 11 is such as to receive the pallet frame with the pallet framesupported on the grid 17. The initial spacing, particularly in regard tothe lower portions of the core and horizontal pressing dies ispredetermined so that when the pressing dies move totheir final positionrelative to the core, all of the mixture therebetween will be compresseda predetermined amount.

The cementitious mixture is prepared with an appropriate amount of waterso that the mixture is in a flocculent state. A predetermined amount ofthe mixture is placed between the core and the horizontal dies,preferably this space is equal to the desired quantity of the mixture,and appears as indicated by '39 in FIGS. 6 and 9.

The mixture is compresed by movement of the pressing dies 23 apredetermined distance toward the core. The walls of the lower portionof the product, including the corners thereof, have essentially uniformthickness. Furthermore, by reason of the fact that the sides of the coreand the corresponding die surfaces 24 and 25 are placed at forty-fivedegree angle to the axis of travel, or nearly so, uniform compression ofthe mixture is attained. This is also essentially true of the materialin the region of the bevel surfaces 27. Still further, it is also trueof the portions of the mixture which form the lateral lower corners ofthe product. Any variation in density is so slight as to be negligible.By way of contrast, this would not be so if the core were cylindricaland the die surfaces were semi-cylindrical. In such case, the densitydecreases laterally and to an increasing degree until at the lateralsides the density is a half or a third that attained at the centralportion. Thus, should a cylindrical shape be desired, a set of fourradially movable dies is used to maintain a more uniform density.

The upper portion of the product by reason of the greater distancebetween the core and the die is initially compresed to a lesser extent.After the horizontal dies have completed their operation, the verticaldie is moved downwardly between the core and the die surfaces tocompress the upper portion vertically until it too attains the samedensity, or nearly so, of the portions of the product below. That is,the excess height of the core and the dies is such that, when the upperportions are compressed vertically from the condition shown in FIGS. 7and 10 to the position shown in FIGS. 8 and 11, the upper portion of theproduct is compressed the same as the lower portion thereof.

After the product has been formed, the vertical 31 and horizontal 23pressing dies are retracted and the hydraulic unit 36 is operated tocause the ejector rods 38 to push upwardly on the pallet frame 34 so asto raise the product above the dies, as indicated in FIG. 1. The productwith its pallet is removed and then cured.

The grating permits excess mixture, if any, to fall downward through thegrating by gravity or an air jet in preparation to receiving anotherpallet to repeat the pressing operation.

Reference is now directed to FIGS. 12 and 13. Should it be desired toprovide a knockout web in a side or end wall, the forming die 23 isprovided with a channel 39 in its underside which accommodates aknockout die plunger 40. The channel 39 is disposed parallel to the axisof travel of the forming die 23; that is, at a forty-five degreerelation to the die face 24 or 25. The plunger 40 terminates in a dieface 41 which is parallel to the die face 24 or 25 and, when extended,confronts a pad or boss 42 formed on the core 19.

A shaft 43 is attached to the plunger and protrudes from the backside ofthe die block and terminates in a head 44 which limits outward movementof the die face 41. A strong coil spring 45 normally holds the die face41 in its extended position.

Alternatively, as shown in FIG. 14, the rearwardly protruding end of theshaft 43 may be provided with a piston which is received in a cylinder46 so that the die face 41 may be extended or retracted hydraulically.

The web forming die operates as follows:

The die face 41 is initially in an extended position to limit the amountof cementitious material received between the die face 41 and boss 42.As the cementitious material is compressed, the die face retracts adistance depending upon the strength of the spring. The spring force maybe such that the cementitious material within the web is less compressedthan the remaining portions of the meter box and, therefore, weaker sothat the web may be readily knocked out.

If the construction shown in FIG. 14 is used, the hydraulic force iscontrolled by conventional means, not shown.

While particular embodiments of this invention have been shown anddescribed, it is not intended to limit the same to the details of theconstructions set forth, but instead, the invention embraces suchchanges, modifications and equivalents of the various parts and theirrelationships as come within the purview of the appended claims.

I claim:

1. A machine for producing a product by press forming a compressiblecementitious mixture, comprising:

(a) a central core having relatively fixed essentially flat angularlyrelated sides facing in opposite directions;

(b) a pair of opposed complementary dies having relatively fixedessentially fiat angularly related die faces disposed essentiallyparallel to corresponding sides of the central core;

() and means for moving the dies in opposition along a common axisbetween an outer position for reception of a predetermined quantity ofcompressible cementitious mixture between the die faces and thecorresponding sides of the core, and an inner position thereby tocompress the mixture between the die faces and the core;

(d) the die faces and core sides forming equal angles with the axis ofmovement of the dies, whereby the density of the product formed by thecompresed mixture is essentially equal to all sides.

2. A machine, as defined in claim 1, wherein:

(a) the central core and confronting surfaces of the dies includingupper and lower ends and the confronting surfaces of the dies, whenclosed, being passed from the core a greater distance at one of theirconfronting ends than at their other confronting ends;

(b) and a die ring is dimensioned to enter between the core and diefaces to effect compression of the mixture in the region of greaterspacing to essentially the same density as the mixture between otherspaced portions of the core and the die faces.

3. A machine, as defined in claim 1, wherein:

(a) a housing supports the core and the opposed dies for horizontalmovement of the dies;

(b) a grating surrounds the base of the core for discharge of excessmixture;

(c) and a pallet ring is removably received on the grating to supportthe resulting product formed by the core and confronting dies forremoval from the core.

4. A machine, as defined in claim 3, wherein:

(a) the central core and confronting surfaces of the dies have greaterspacing at their top portions;

(b) a vertically movable die ring is supported above the core forvertical movement into the space between the upper portions of the coreand die surfaces after initial compression of the mixture therein,thereby to effect further compression of the mixture in a verticaldirection to increase its density to that of the mixture below.

5. A machine for producing a product by press forming a compressiblecementitious mixture, comprising:

(a) a central core;

(b) a pair of opposed complementary dies having die faces confrontingopposite sides of the core;

(0) means for moving the dies in opposition along a common axis betweenan outer position for reception of a compressible cementitious mixturebetween the die faces and the core, and an inner position thereby tocompress the mixture between the die faces and the core;

(d) a web forming die having a fixed die element and confronting amovable die element protruding into the space between the core toreceive a lesser quantity of cementitious material therebetween;

(e) and yieldable means backing the movable die element thereby to applya predetermined compression force on the cementitious materialtherebetween independently of the force applied to the remainingcementitious material.

References Cited UNITED STATES PATENTS 3,162,895 12/1964 Busch 18-5 R3,090,093 5/1963 Long 25-45 3,058,153 10/1962 Busch 18DIG. 58 3,484,51012/1969 Corazza 18-5 P X 3,566,442 3/1971 Hakala 18-5 P X H. A. KILBY,1a., Primary Examiner US. Cl. X.R.

